Battery fully charged, but when it rains it won't start without a jump

I have seen this question asked here before, but my problem seems slightly different, so I apologize if it seems like a repeat:

I drove in a rain storm yesterday…stopped to get gas…car would not start afterward, but my lights and radio were still working. Got the car jumped, drove it around, took it home and shut it off and immediately tried to start it again–dead. Let it sit over night. Would not start–engine lights worked etc–would not start. Checked the battery it still had a full charge. Drove it again. Shut it off still had all the lights and radio. I am pretty sure it has something to do with the rain (the only time it ever stalled before was twice in the rain). My question is: if it’s either the ignition switch or maybe the spark plugs or distributor cap–why would it still start after a jump?? I didn’t think one had anything to do with the other.

Does the engine crank or not when you try to start it? If it does not crank, do you hear a click when you try to start it? The click is the starter solenoid. Sometimes a broken tooth on the flywheel will allow the starter to run, but the engine wont turn over. In the latter case, put the vehicle in gear and push it three feet, and then try again. The rain may not be part of the problem.
Also, a battery conn. that is poor will work sometimes and not others. In this case there will be no cranking, and no click of the solenoid.
Remove the ground conn from the battery, and clean the post and lug with a wire terminal brush. Wash the top of the battery with baking soda. rinse it. remove the the pos. lug and clean the post and lug with the wire brush. Check the water level in the battery, and top it up to the mark with distilled water. Reconnect the pos. terminal, and with an acid brush and some vaseline, coat the exposed surfaces. Do the same to the neg terminal. and see if that fixes your problem. This is cheap, easy and inexpensive. Be sure to wear rubber gloves and avoid splashing any acid on your cloths. Wear eye protection too.

My first guess is a bad contact at the battery or at the other end of a battery cable.

Remove each end of each cable and clean it and where it attaches. (It is also possible to have an internal failure in a battery cable.

Definitely sounds like you need a new battery, age of yours? Sure it could be a myriad of other problems but if it starts with a jump and your charging system is good, battery is suspect. How did you determine the battery had a full charge?

Thank you for all the great responses!

Let me just say: I am completely clueless about cars but I am trying to learn everything I can, becuase most times I leave a shop feeling like the mechanic is just as clueless as I am, and is just taking a stab in the dark and charging me for the favor. I had a very dangerous problem a few months ago–life and death really–and it was missed by TWO garages. I am lucky to be walking around AND it was darn expensive! That was the last straw.

If I recall correctly I haven’t changed the battery in about 4 yrs… I had the voltage checked this morning before it was jumped it was 12.5 after it was above 14.

I will show my denseness here: can a battery cable be replaced?

I just had the battery “serviced” last month when I had an oil change at the dealer because when I was adding wiper fluid I noticed the battery was filthy. They supposedly took the whole thing apart, coated it etc. Charged me 20.00 so I hope they did what they were supposed to do.

I still can’t understand how I still had power to my cd player and all the lights (even the phone charger flipped on) but the car would only start with a jump and wouldn’t turn over again after I shut it off. Like I said I am really dense when it comes to cars, but it has been raining non-stop for 2 days I have driven over some massive puddles (unavoidable), and for some reason I think something got wet (?).

I will certainly check all of these things, but I have no way of doing it myself really. Yes, I am a girl, not that there’s anything wrong with that! I can learn, I just have never done any type of car maintenance:)

Just because your lights and cd player work does not mean your battery is good.

The starter motor can draw a few hundred amps, while lights only draw maybe 10 amps. If all battery cables and connections are good I would say its the battery because the car starts with a jump.

Its not unusual for a 4 year old battery to fail. Here in hot Florida most batteries only last 3 - 4 years.

If you go over to an Autozone or another auto place they can usually load test the battery.

Showing 14 volts when engine is running rules out the alternator.

The engine just clicks when I try to start it. I did try putting it in neutral --nothing. However, as I said when I turn the key all of the dash and engine lights come on as does the radio and cd, etc. I guess I will just have to have the battery tested and go from there. I don’t want to replace it if it’s not the problem, but as all of the replies below state–that’s probably the issue.

It is very possible that the battery is on its way out since it is 4 years old and a new one will fix the trouble. You should get the charging system load tested to see what the condition of the alternator and battery are and go from there. The click you hear may very well indicate the trouble is with the starter solenoid contacts and if so replacing the battery would not fix the real problem.

I am going to have the charging system tested tomorrow (if they can fit me in ). I’m pretty sure that’s what is causing the problem, since the car will only start if it’s jumped. Luckily-- if it is the starter solenoid it will be covered by my warranty.

Turns out it WAS the battery. Although I had it “serviced” last month, the dealer I took it to apparently never checked the voltage or for that matter cleaned it properly. I think all they did was clean off the top and put some lube stuff at the connector sites (?) It was still really filthy and was leaking all over the place. Anyway new battery is great.

You can not test a battery just by measuring the voltage. You have to measure the voltage with a known heavy load applied (load test) to get any indication of the battery’s condition. I wouldn’t normally expect them to load test the battery during serving unless you asked them to or related some event that would cause them to suspect a battery problem.

I have and am experiencing the same thing except for mine would not crank the first time. Had it towed to the dealership (chevy ) they ran a diagnostic report and said it was a bad battery. Replace with a new battery and low and behold experienced heavy rain again an the exact same results…less than 3 weeks of having new battery replaced. HELP 08 C6

It’s better to start a new thread than to tag on to a 10 year old one. Many regulars skip over old threads.

You probably have a dirty or loose connection somewhere in the charging circuit. You new battery ran the car fine, but eventually ran out of power and was not recharging well in the wet conditions.